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When ground wires burn it's usually from loss of a higher amperage major ground failure and the power circuit it provides ground for, goes looking for what and wherever it can find a ground.

GMs had a propensity to burn a 10 gauge auxiliary ground from the battery post that went to the body when the main grount from the battery cable to the engine block started to become resistant at the connex at the thermostat or on the alternator adjustment bracket.

That wire would then try to carry the cranking ground ... which it was want not to do! It would smoke and do pretty much what I see in your picture.

Too bad ... because hunting bad grounds is hard.

Unless this is typical and a common problem, you may just have to search it out blindly.

I'm sure someone will be along with their knowledge soon.

In the ,meantime ... I'm subscribed too.
 

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2002 trailblazer main ground wires on the passenger side floor started smoking and are now burnt. View attachment 58037

Possibly a bad/dirty connection or a blower motor on the way out and drawing high current. That should have blown a fuse though. I think the blower motor is the highest current draw there. That ground serves a boatload of circuits.
 

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The thing that grabs my nethers is that there's an ultimate current limiter hidden in the black plastic casting that the blower resistor pack is laminated to.

I do not believe it could allow enough current go smoke that ground wire.

About that current limiter ....

You can't see it ... well, if you CAN see it you've taken it past any state of repairability.
Been there.​
Done that.​
Over n over.​

It's (so far) not repairable (I ran out of test victims a while back and keep asking my friends to save me their old ones for autopsies) ... well ... it's not YET repairable ... but I'm gaining on them!

FWIW -----> one cannot solder on that circuit board .... it's got a self destruct antimony or some goofy low-teml flowing solder for the traces and soldering jumpers on the PC board won't work.

It won't. Believe me ... even if you haven't in the past.

I figger maybe three more blower resistor cadavers and my monster will be alive!
ALIVE!​
ALIVE!

Some day I might go into the heater blower resistor repair business ... certainly a niche needing to be filled!
 

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But a poor connection can generate a whole lot of heat.
If we're talking the HVAC blower - then I don't believe it can actually pull that much amperage to smoke-o that wire.

YES heat at the connex if the HVAC blower ground becomes a substitute for some other circuit - or circuits that can be found to be relying on a single path to ground that also happens to be in the HVAC ground wiring circuit.

Like my own TB - I found that singularity for a ground under the console to be somewhat corroded and I buffed it down to bare metal. fluxed and soldered it and used a couple of internal spur lock washers to make a cutting circuit. So far --- so good.

I believe that a stack of ground lugs on a single nut-n-stud can generate their own resistance and a lot of heat too - I've seen it myself.

I just cannot fathom that the HVAC blower circuit can generate that much heat all by itself and especially to heat the wires like that --- but I've been wrong before.

When I finally get into that resistor card and find out the breaking point of the master fusible link in it - then I bet I'll have a lot more insight into what it takes to pop it once and for all. I've seen the blower pull 15 Amps.

Betting that those super smart engineers have added a little safety on top of the correct current pull; it may pop at 22 Amps or so.
 

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I bet the engineers gave a little more slack to the fuse than I thought. I guess the startup surge is a lot higher than 22 Amps!

I was just spitballing there.

Yeah - I agree with your proposition --- that area is overheated.
 
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